In the semiconductor manufacturing field, the size of a wafer tends to increase year by year. In order to improve a packing density, the thickness of a wafer tends to be reduced. In order to reduce the thickness of a wafer, an underside grinding operation is carried out, i.e., a surface protection tape is adhered to a right side of a wafer provided with a plurality of semiconductor devices, and, then, the underside of the wafer is ground while the surface of the wafer is sucked and held. After that, a dicing operation is carried out, i.e., the wafer is cut into dice. The wafer is attached to a frame because the mechanical strength of a thin wafer whose underside is ground is remarkably reduced and, thus, it is easy to handle the wafer in a subsequent process in which, for example, a dicing operation is carried out. FIG. 2b is a sectional view of a wafer attached to a frame. As shown in FIG. 2b, after a dicing tape 21 is adhered to the underside of a wafer 12 whose right side is usually provided with a surface protection tape 11, the wafer 12 is mounted to a frame 15 together with the dicing tape 21 and, then, the dicing tape 21 is appropriately cut. After the surface protection tape 11 is detached, the wafer is diced in a dicing process. The dicing tape 21 to be used usually has a property in which the hardness thereof is increased and the adhesive force thereof is reduced due to ultraviolet light irradiation. Therefore, the dicing tape 21 is cured to a certain extent by irradiating the dicing tape 21 with ultraviolet light and, thus, a portion of the dicing tape 21 is prevented from being adhered to a blade of a dicer in the dicing process (See, for example, Japanese Unexamined Patent Publication (Kokai) No. 10-27836, Japanese Unexamined Patent Publication (Kokai) No. 10-284564 and Japanese Unexamined Patent Publication (Kokai) No. 7-183365).
However, there are, in fact, various kinds of the surface protection tape 11 and the dicing tape 21 which have different properties. In, for example, the surface protection tape 11, there are a tape having a property in which the hardness thereof is increased and the adhesive force thereof is reduced due to ultraviolet light irradiation, and a tape having a property in which the hardness and adhesive force thereof do not vary when it is subject to ultraviolet light irradiation. Likewise, in the dicing tape 21, there are a tape having a property in which the hardness thereof is increased and the adhesive force thereof is reduced due to ultraviolet light irradiation, and a tape having a property in which the hardness and the like thereof do not vary when it is subject to ultraviolet light irradiation. Therefore, it is preferable that the wafer be processed in view of the properties of the surface protection tape 11 and the dicing tape 21.
Especially, when the dicing tape 21 having a property in which the adhesive force thereof is reduced due to ultraviolet light irradiation, is used, and the surface protection tape 11 is detached after the dicing tape 21 is irradiated with ultraviolet light, the surface protection tape 11 sometimes pulls the wafer 12 to damage the wafer because there is a possibility that the adhesive force of the surface protection tape 11 may be larger than that of the dicing tape 11. Therefore, it is extremely important to handle the wafer 12 in accordance with the properties of the surface protection tape 11 and the dicing tape 21 and, particularly, the reaction with ultraviolet light.